Domestic heating stove



June 12, 1923.

' H. DOHERTY DOMESTIC HEATING STOVE Filed Sept. 8, 1920 nueuloz Patented June l2, i923.

METRE S'Ttlfi:

at i.

HENRY L. IDOHERTY, 01 NEW YORK, N. Y., ASSIGNOR TO DOHERTY RESEARCH COlVI- PANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

DOMESTIC HEATING STOVE.

Application filed September -T (LZZ whom it may concern Be it known that I, HENRY L. DOHERTY, a citizen of the United States, residing at New York city, in the county of New York, State of New York, have invented certain new and useful Improvements in Domestic Heating Stoves; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use'the same.

This invention relates to domestic heating stoves and more particularly to a method of and apparatus for heating the interior of buildings.

In heating a building by means of stoves or other fuel burning heaters placed in the rooms of the building, it is advantageous to obtain as much as possible of the heat of combustion of the fuel in the form of radiant energy and to distribute the heat throughout the room by direct radiation rather than by conduction and convection. hen convection currents are relied on for distributingheat, the bodies of air heated by contact with the stove tend to rise to the upper part of the room and to form heat zones or strata which increase in temperature toward the upper part of the room. As a result, the upper part of the room Will be overheated before the lower part .is heated to the desired temperature, and an unsatisfactory distribution of heat is obtained. When heat is transferred by radiation directly from the stove to the space to be heated, the heat is projected from the radiating body with equal force in all directions and may be directed or reflected in any di rection or to any part of the room. Accordingly the tendency for heat to be carried to theupper part of the room by rising currents of air may be counter-acted by directing the radiated heat to the lower portions of the room and a better control of the heat distribution may thus be obtained. Moreover, when radiation takes places from an incancescent or glowing body, a very pleasing lighting effect is produced which adds greatly to the attractiveness of this manner of heating.

When gas is used as a fuel. it is, however, difficult to obtain the heat of combustion in the form of radiant energy; 'This is largely due to the fact that the heat produced by the combustion of gas is not generated in Serial No. 408,970.

inert gases of low temperature which enter the stove outside of the burner and mix with the flame. Since the rate of radiation of heat is proportional to the fourth power of the absolute temperature of the radiating body, arsmall drop in temperature causes a relatively large drop in the quantity of heat radiated. As a result of the lower radiation effects obtained in the type of stove heretofore used, the heat has been transferred from the stove and distributed throughout the room largely by conduction and by convection currents with a: consequent loss in efliciency and lack of uniformity of distribution.

A further loss of heat results from the entrance of an excess of air to the stove, because the volume of heated exhaust gases is thereby increased and a correspondingly larger amount of heat passes to the chimney. Because of the difliculty of efiiciently utilizing and readily controlling the distribution of heat formed by the combustion of gas in the type of stoves heretofore used, the use of gas as a fuel for heating purposes has been greatly restricted, even in cases whereonly a temporary and moderate heat is required and where the use of gas would be particularly advantageous because of its convenience and cleanliness.

The primary object of the present invention is to provide a gas heating stove in which a maximum etficiency in the combustion and distribution of heat is obtained.

Another object of the invention is to provide a gas fired heating stovein which a maximum amount of the heat of combustion of the gas is obtained in the form of radiant energy.

A further object of the invention is to provide a domestic heating stove in which the quantity of heat carried in the exhaust gases is reduced to a minimum. I

A further object of the invention is to provide a method of heating with gas in which a maximum efiiciency in combustion and in the distribution of heat is obtained.

With these and other objects in VlQIW,/Cli

invention consistsinthe apparatus;described:

in the following specification and particularly defined in the claims.

The various features of the invention'are shown in the. accompanying drawing in which:

Fig. 1 is a sectional view inv elevation of a gas fired heating stove, embodying a preferred form of the inventiongand Fig. 2 is a vertical sectional view of the stove,taken on the line 2-2 of Fig. 1.

The greatest efliciency in the utilization of th heat of combustion of the gas will be obtained when the minimum amount of air necessary for complete combustion is supplied to the stove. The addition of air over this minimum reduces the e'l'liciency by cooling the flame and also by increasing the quantity of heat carried froni-the stove by the exhaust gases. In the present invention the lossescausedthrough the entrance of an excess of air to the combustion chamber of the stove is prevented by supplyingthe air in a. definite proportion to the rateof supply .of'the fuel gas and adjusting theproportion of air to gas: togive the minimum amount l combustion chamber at a rate proportional to the supply of gas. The combustion chamber in which the gas is burnedis tightly closed to prevent theentrance of any additional air. enter the combustion chamber in aconstant and definite pro-portion to insure perfect combustion and the volume of exhaust gases leaving the combustion chamber, and accordingly the heat passing to the chimney, is thereby reduced to a minimum.

The heat lost in the exhaust gases is still further decreased and the efliciency of the stove incre'ased by transferring heat from the exhaust gasesto the-ingo-ing air by means of'a' suitable heat interchanger. By'thus re turning-the waste heat of the exhaust gases to the combustion chambenthe temperature 7 of the flame is raised and its heat radiating power 'correspondmgly increased.

In preheatingthe entering air, the air passes from the air forcing meter to the combustion chamber through a .numberof pipes or tubes surrounded by the hot products of combus tion leaving the combustion chamber and is thereby heated before it enters thegas flame.

In the embodiment of the invention shown in the accompanying drawings, the meters for stove For this purpose fuel gas under pres- By this means. the gas andair.

sure enters a meter chamber 10 through a pipe 12 and is deliveredtoone end of a gas forming one end-of a series of measuring pockets.

26 which extend from the cylindrical wall of the drum 14 inwardly under the level of water in the chamber 10 and connect with end walls 19 and 28 which extend from the edge of one blade to within a short distancev of an adjacent blade. The pitch and the number of the bladesv 20-26, and the size.

of the endwalls 19and 28 are so adjusted to the level of water in the chamber 10' and the The measuring pockets are formed by a series of helical blades 20, 22, 24 and drum 14 that the frontedge ofone end wall,

at the inlet end of the'drum, will dip into the Water in the chamber 10 before the rearedge of the preceding end wall, at the outlet end of the drum, risesabove the surface of the water level. In this manner thereis always one blade whose end. walls extend,

below the surface of the water and seal the passageway through the drum. The pres- ;sure of the gas entering. from the pipe 12- acts on the spiral blades to produce a'resultant force which rotates the drum-14 and thus passes the bodies of gas enclosed betweenadjacent blades to the opposite end of the drum. The rotation of the. drum will thus beproportional to the rate .atwhich the gas passes through the drum. After passing through the measuring pockets. of the drum 14, the gas is received in a compartment. 29 formed in the chamber 10 above the. water level andbetween. walls of the chamber and a partition 80 extending from the top of the chamber into the body of water contained therein. From the compartment 29 the gas is delivered through a, pipe 32to a domeshaped combustion chamber 34..

. Air for supporting combustion of the gas I and forced tovthe combustionchamber by the rotation of an air meter drum 4O mountin the combustion chamber 84 is'measu'red 'ofw'ate-r in the drum 40 and is received be:v

tween an end wall 44 of the drum and the end wall 45 .of a series of measuring pockets. The-measuringpockets are formeduby a se-x vries ofhelical blades 46, 48,50 and 52 which extendfromthe cylindrical wall of the drum 4O inwardly below the level of the Water in the drum and connect with end walls and 53 which extend from the edge of one blade to within a short distance of a preceding or following blade. -The blades 46, 48, and 52, and the end walls 45 and 53 are so proportioned in relation to the level of the water in the chamber 10 that the edge of one end wall, nearest the inlet pipe 42, will dip into the surface of the water before the edge of the end wall of the preceding blade, at the outlet end of the drum, rises out of the surface of the water. As the edge of the inlet end wall dips below the surface of the water, it encloses a quantity L of air between the helical blade to which it is attached and the preceding blade, and as the drum. continues to rot-ate, this air is forced to the opposite or outlet end of the drum.

The drum 40 is larger than the drum 14 inasmuch as the volume of air required for combustion will be several times the volume of the gas being burned. In cases where the stove is madefor use with a particular gas, and in which it is not desired to vary the proportion of gas and air, the diameter of the drums 14 and 40 will be the same, and the length of the drums will be proportional to the quantity of gas and air supplied to the combustion chamber. With this construction, the proportion of gas and air will be constant regardless of the level of the water in the chamber 10. In case the stoves may be used With gases of different composition which require different amounts of air for complete combustion, it will be necessary to vary the rates at which gas and air are supplied. This may be conveniently done by making the drums of different diameters, in which casethe proportions of gas and air may be varied by varying the level of the water in the chamber 10. From the opposite end of the drum 40 the air passes through slots 53 formed between the edge of the end wall and a succeeding blade into an air receiving chamber 54 from which it passes into the heat receiving unit of a heat interchanger.

In the heat interchanger, the air is heated before passing to the combustion chamber by abstracting heat from. the products of combustion leaving the combustion chamber. The heat interchanger comprises a chamber 55 positioned between the gas meter 10 and the combustion chamber 34 and a series of tubes forming the heat receiving unit of the heat interchanger, through which air passes from the chamber 54 to the combustion chamber 34. Hot products of combustion from the combustion chamber 34 flow through the heat interchan e chamber 55 and are directed into conta ct with the heat receiving tubes 60 by means of baffles 62 and 64 positioned within the heat interchange chamber 55. In passing through the heat interchanger, the air from the chamber 54 flows in a countercurrent direction to the hot exhaust gases from the combustion chamber 34. To this end,

the air from the chamber 54 passes through a connecting nipple 56 into a distributing manifold 58 in which it is distributed to a number of parallel tubes 60 in the chamber 55. The tubes 60 pass back and forth between baflies 62 and 64 in the heat interchange chamber and deliver the air to a receiving manifold 66 in the upper part of the chamber. From the manifold 66, the air which has been heated in its passage through the tubes 60 is delivered to the central part of the combustion chamber 34 through an air delivery pipe 68 opening adjacent the end of the'gas delivery pipe 32. The interchanger or recuperator and the gas and air delivery pipes 32 and 68 are subjected to much higher temperatures than these produced in an ordinary heating stove and are preferably made of Monel metal or of calorized or sherardized sheet metal in order to decrease or eliminate oxidation of the metal.

By means of the. above described interchange of heat, practically allof the heat carried by the products of combustion is recovered and returned to the combustion chamber where it is added to that radiated directly to the room to be heated. The gases leaving the combustion chamber must nece sarily be of the same temperature as the combustion chamber and will, therefore. carry with them a considerable amount of heat. While the proportion of the quantity of heat radiated to the quantitv carried by the hot gases is greater the higher the temperature, since radiation varies with the fourth power of temperature, and the quantity of heat carried by the gases varies approximately directly with the temperature, a very large amount of heat is nevertheless carried by the exhaust gases. Moreover, it

is not desirable to have gases at the temperatures prevailing in the combustion chamber pass directly to the exhaust flue or chimney. With the above interchange of heat between the products of combustion and the ingoing air, the exhaust products of combustion are cooled to substantially atmospheric temperature and the heat of the exhaust gases'is thereby transferred to the ingoing airand returned to the combustion chamber. The incoming air is thereby raised to approximately the ten'iperature at which combustion takes place, and accordingly very little of the heat of combustion is used in heating the. incoming gases so that substantially all of the heat ofcon'ibustion is radiated directly from the walls of the combustion chamber. The. etliciency and completeness of the interchange of heat is promoted by the fact that a minimum quantity of gases. is involved; dueto. the

a1r and gas measuring devices. I

.The highly heated air from the pipe 68 proper propo-rtioning of air andgas, by the .inixes with the gas delivered by thepipe 32 and rises as a flame to'the top of the combustion dome 34. Onreachingthe top. oft-he;

dome, the flame is. deflected downwardly and flows in alayer adjacent the inner wall .to the bottom of the dome. In.'passing" downwardly in' contact with the walls of the dome 34, the flaming gases heat the dome to incandescence and provide excellent condie tions for the radiation of heat. The air and.

' gas enteringthrough the pipes .32: andGS are surroundedby a glowing lay'eroflgases and by the heated'walls oi -the chamber 3a, which eliminatesall danger otchilling of the gases and insures a rapid and thorough combustion of. the. entering gases. By means of: this construction complete combustion will have .been obtained by the time the gases reach the upper part of the dome and the gases will be brought into contact with the walls oft-the dome at the highest possible temperature and under conditions most tavorablefliiorthe transfer of heat. by radiation from the surface of the dome3l toward-the floor of the room to be heated, The dome 3 1i: is preferably constructed of silica, ni'crom. or.

other heat resisting material capable of being heated to incandescence without deteri oration, and is preferably providediwith a surface having a high radiating power or ii emissivity in order to increase the quantity.

' 0t heat radiated.

The exhaust gases from the chamber containing a certain amount of residual heat pass downwardly into the heat interchange chamber'55 between the bjaflies .62 andfia and V are brought into intimate contact withthe Qair heating tubes 60. By this contact with the tubes the residual'heat of the waste .products of combustion passes to the air within the tubes 60 and'is returned to the combustion chamber 34 while the residual gases are restored to substantially atmo pheric temperature.

In similar manner, the g s P ssing through'the gas supply tube82 is preheated "by the hot products of-combustionh When a gas consisting essentially of' hydrocarbons is used, n whlch case the volume "of air necessary for complete combustionis several 'times greater than the volume of gas, and

there 'isa tendency for-the gases to decompose and deposit carbonupon being heated, a comparatively short tube such as that shown in the drawings is employed. When water gas or producer gas, or"similar gases having a comparatively lower heating value and employing relativelysmaller volumes of air and larger volumes of gas are used, a

system of heat receiving tubes similar to the air tubes 60 should be employed.

ess n:

When the fuel gasused in .the stove, con tains a considerableamount of hydrogen or hydrocarbons, water. vapor willbetormed 69..connects thebottom of the chamber 55 to the lower part of the .i'neter chamber 10. An overflow pipe is providedonthemeter,

chamber 10 to prevent the accumulation of water from the pipe 69 and to maintain a.

constant levelin the chamber.

' It is preferred, in the interests o t lproper. ventilation, thatthe waste products leaving the chamber 55 should be conducted to the outside atmosphere. from the chamber are, therefore, ordinarily The exhaust gases passed through anoutlet 71 to a chimney and exhaustedto the atmosphere, Incase it is not convenient to exhaust the flue products to the outsideatmosphere, it will be found that the condensation of water in the heat interchange chamber 55 will remove thegreater part. ofthe excc-issive humidity which is zalwaysipresent when open gas stoves are employed. The exhaustproducts will, accordingly,'not have the deleterious effects usually produced by exhaust products of gas stoves.

To directthe heat radiated from the dome,

34. to the lower part oftheroonna reflector T2 is supported over the .domei'ld-byineans of standards 74-. restingv on the heat interchanger chamber 55. In casethe reflector '72 concentrates theradiatedheatto one spot.

in front of the stove, a screen? 5 arranged to-permit theheat rays to pass but having a: diffusing. effect on therays, may; be pro vided. A door 76' isprovidedcin.the dome 84 through which the gas mayybe ignited in starting the stove.

ways delivered by theair meterACO.

Having described the invention, what isv claimed as new is: i

1. A method of heating dwellingsor other buildings-comprising mixing air and gas in".

such proportions as will produce complete combustion of said air and gas, igniting said mixture 111 the interior of closed combustion chamber otretractory: readily incantion chamber in a definite desired direction. 2. A method of heating dwellings or other buildings comprising mixing. air and gas in such .PIOPOIJDIQHS aswill produce complete combustlon of said alr and gas, ignltlngsald mixture in the'interior of a closedcombus- The door .is closed when the stove is inoperatlon, since'the proper amount of air 'lf OI' COIIlbuSi/lOILClS al-' descent material, maintaining. a. high flame j I temperature of said burning products in. contact with the-walls of said chamber, and reflecting the radiant heat of the combusber to develo a hi h flame tem erature and reflecting the'ra-diant heat of the combustion chamber in a definite direction.. v

- A method of heating dwellings or other buildings, comprising mixing 'air and gas in such proportions as will produce complete Combustion of said air and gas, ignitingsaid -mixture in the interior of a closed combustion chamber of refractory readily lncandescent material, using gas under pressure for positively introducing said gas and air in a definite ratio into said chamber, passing the products of combustion into contact with the walls of said chamber, maintaining substantially the maximum flame temperature by preheating the products for combustion with the hot products of combustion exhausting from the combustion chamber, and reflecting the radiant heat of the com bustion chamber in a definite direction.

4t. A gas heating stove, comprising a combustion chamber of heat refractory material, a gas meter arranged to measure gas passing to said combustion chamber, an air meter driven by said gas meter arranged to pass measured quantities of air to said combustion. chamber, an air conduit leading from said. air meter to said combustion chamber, a gas conduit leading from said gas meter to said combustion chamber, and an exhaust fine leading from said combustion chamber n heat conducting relation to said air conduit, and a reflector over said chamber.

A. gas heating stove, comprising a combustion chamber, means for collecting gas and air in measured proportions, air and conduits leading from said air collecting means to said combustion chamber, and an exhaust flue leading from said combustion chamber in heat conducting relation to said conduits.

6. A gas heating stove, comprising a gas meter, an air measuring and forcing meter driven by said gas meter, a closed combustion chamber, means for introducing and mixing the gas and air from said meters within said chamber, and means for exhausting the products of combustion from said chamber.

7. The combination with a gas heating stove, of a gas measuring means, means operated by said gas measuring means for forcing air into said stove in a definite proportion to the passage of gas through said meter, a closed combustion chamber, a heat interchanger, means for passing air from said air measuring means through passageways in said heat interchanger, and means for forcing products of combustion from said combustion chamber through said heat interch anger.

8. A gas heating stove, comprising a gas measuring means, an air measuring means driven by said gas measuring means and -.r

positioned to force air to said stove in definite relation to the passage ofgas through said meter, a closed combustion chamber, havinganexhaust gas passage at its bottom,

means to mix the measured air and gas within the combustion chamber, and means for interchanging heat from the exhaust gases from said combustion chamber with the air passing from said air meter to said combustion chamber.

9. A gas heating stove, comprising a combustion chamber, a gas meter operated by gas passing to said combustion chamber, an air meter driven by said gas meter, arranged to force measured quantities of air to said combustion chamber, conduits for leading air and gas from said meters to said combustion chamber, an exhaust flue leading from said combustion chamber in heatconducting relation to said air conduit, and a water by-pass pipe leading from the lower part of said exhaust fine to said gas meter.

10. A gas heating stove, comprising a meter chamber, an exhaust gas chamber on said meter chamber, battles mounted in said exhaust gas chamber, a combustion chamber on said exhaust gas chamber, a gas pipe leading from said meter chamber to said combustion chamber, an air supply pipe leading from said meter chamber between said bafiies to said combustion chamber, and

inter-connected air and gas meters in saidmeter chamber adapted upon rotation to pass air and gas to said air and gas pipes respectively in definite measured proportions. 7

11. A gas fired heating stove, comprising a closed combustion chamber and means for positively delivering gas and air separately to the interior of said combustion chamber in a definite fixed ratio.

12. A gas fired heating stove, comprising a meter chamber, a shaft in said meter chamber, a gas meter drum on said shaft, an air meter drum on said shaft, a dividing partition in said meter chamber between said gas meter drum and said air meter drum and dividing said chamber into an air compartment and a gas compartment, a heat interchange chamber, a combustion chamber, a conduit leading from said air meter compartment through said heat interchangechamber to said combustion chamber, and

means for exhausting gases from said coma closed combustion chamber, a heat inter change means for interchanging heat be tween the exhaust gases from said combustio'n chamber and the-"ail" entering ."s'ai'd combustion chamber, and means'for'remov 'ingfithe moisture 'c'ondensd "from said exfhsdustigases in v tfrractory material "capable "of becoming incandescent :nthi-gh 'omperatui-es, means for deliw 'eri'n'giair and gas in measured proportions into the interior "of said *coinbii'stion chai'nbei', means for ithdrawing t1ie .prot1- "nits of'combustion "from'the bottom of said c'omloustio'n"chamber, and a reflector over said combustion chamber.

15. A iiiethod of heating dwellings or Qt-hm" bliildiings ooinpfisin'g mixing air-and 'T'gas in measured: pi'oportions' to produce coni j o'lete mnbu'stion thereof, igniting the mixtuie in :the interior of a closed combus- "1011 chamber of "a refractory readily incande'soenbinatrial, *p ztssing "products of -combustio i'iiitooontactfwith'the interior walls tially the maximixm flame femperaturowifih- 

